Wireless power transfer (WPT) involves the transmission of power from a power transmitting unit (PTU) to one or more power receiving units (PRU). For instance, in one typical application, a charging pad for portable electronic devices uses near-field electromagnetic coupling of power to power-receiving devices such as smartphones, accessories (e.g., wireless headphones), and similar devices. In general operation, when a PRU is placed engaged for WPT with a PTU, the PRU is positioned relative to the PTU so that the electromagnetic coupling may take place. In addition, a separate wireless communication link may be established over which the PTU and PRU can coordinate their WPT-related operations, including session and power control management.
In applications where a single PTU can support multiple PRUs, a cross-connection problem may manifest in situations where a PRU is located within wireless communication proximity with two or more PTUs. A practical solution is needed to better address the issues with cross-connection.